[PATCH] D99037: [Matrix] Implement explicit type conversions for matrix types

Wed Mar 24 14:59:32 PDT 2021

SaurabhJha added a comment.

Hey @fhahn ,

I realise, as you pointed out before, that we need to do some changes in CodeGen too. I think its going to be more involved so before starting on that, it would be great if you can confirm whether I am on the right path. I will describe what I did, what happened, and what I inferred from that.

I ran this simple cast.

  typedef char cx4x4 __attribute__((matrix_type(4, 4)));
  typedef int ix4x4 __attribute__((matrix_type(4, 4)));
  cx4x4 c = (cx4x4) i;

This crashed the compiler with this stack trace.

  clang: /tmp/llvm/lib/IR/Instructions.cpp:2934: static llvm::CastInst *llvm::CastInst::Create(Instruction::CastOps, llvm::Value *, llvm::Type *, const llvm::Twine &, llvm::Instruction *): Assertion `castIsValid(op, S, Ty) && "Invalid cast!"' failed.
  PLEASE submit a bug report to https://bugs.llvm.org/ and include the crash backtrace, preprocessed source, and associated run script.
  Stack dump:
  0.	Program arguments: /tmp/build/bin/clang -cc1 -internal-isystem /tmp/build/lib/clang/13.0.0/include -nostdsysteminc -fenable-matrix -triple x86_64-apple-darwin /tmp/clang/test/CodeGen/matrix-cast.c -emit-llvm -disable-llvm-passes -o -
  1.	<eof> parser at end of file
  2.	/tmp/clang/test/CodeGen/matrix-cast.c:15:6: LLVM IR generation of declaration 'cast_char_matrix_to_int_same_size'
  3.	/tmp/clang/test/CodeGen/matrix-cast.c:15:6: Generating code for declaration 'cast_char_matrix_to_int_same_size'
   #0 0x000000000972648a llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) /tmp/llvm/lib/Support/Unix/Signals.inc:565:11
   #1 0x000000000972665b PrintStackTraceSignalHandler(void*) /tmp/llvm/lib/Support/Unix/Signals.inc:632:1
   #2 0x0000000009724c4b llvm::sys::RunSignalHandlers() /tmp/llvm/lib/Support/Signals.cpp:70:5
   #3 0x0000000009726dd1 SignalHandler(int) /tmp/llvm/lib/Support/Unix/Signals.inc:407:1
   #4 0x00007ff3d17353c0 __restore_rt (/lib/x86_64-linux-gnu/libpthread.so.0+0x153c0)
   #5 0x00007ff3d11e618b raise /build/glibc-eX1tMB/glibc-2.31/signal/../sysdeps/unix/sysv/linux/raise.c:51:1
   #6 0x00007ff3d11c5859 abort /build/glibc-eX1tMB/glibc-2.31/stdlib/abort.c:81:7
   #7 0x00007ff3d11c5729 get_sysdep_segment_value /build/glibc-eX1tMB/glibc-2.31/intl/loadmsgcat.c:509:8
   #8 0x00007ff3d11c5729 _nl_load_domain /build/glibc-eX1tMB/glibc-2.31/intl/loadmsgcat.c:970:34
   #9 0x00007ff3d11d6f36 (/lib/x86_64-linux-gnu/libc.so.6+0x36f36)
  #10 0x0000000008a5c1bf llvm::CastInst::Create(llvm::Instruction::CastOps, llvm::Value*, llvm::Type*, llvm::Twine const&, llvm::Instruction*) /tmp/llvm/lib/IR/Instructions.cpp:2936:11
  #11 0x0000000006205834 llvm::IRBuilderBase::CreateCast(llvm::Instruction::CastOps, llvm::Value*, llvm::Type*, llvm::Twine const&) /tmp/llvm/include/llvm/IR/IRBuilder.h:2106:52
  #12 0x00000000061ef472 llvm::IRBuilderBase::CreateBitCast(llvm::Value*, llvm::Type*, llvm::Twine const&) /tmp/llvm/include/llvm/IR/IRBuilder.h:2065:5
  #13 0x0000000009fb1140 (anonymous namespace)::ScalarExprEmitter::VisitCastExpr(clang::CastExpr*) /tmp/clang/lib/CodeGen/CGExprScalar.cpp:2069:5
  #14 0x0000000009fb002e (anonymous namespace)::ScalarExprEmitter::VisitExplicitCastExpr(clang::ExplicitCastExpr*) /tmp/clang/lib/CodeGen/CGExprScalar.cpp:563:5
  #15 0x0000000009fa8493 clang::StmtVisitorBase<std::add_pointer, (anonymous namespace)::ScalarExprEmitter, llvm::Value*>::VisitCStyleCastExpr(clang::CStyleCastExpr*) /tmp/build/tools/clang/include/clang/AST/StmtNodes.inc:879:1
  #16 0x0000000009fa2747 clang::StmtVisitorBase<std::add_pointer, (anonymous namespace)::ScalarExprEmitter, llvm::Value*>::Visit(clang::Stmt*) /tmp/build/tools/clang/include/clang/AST/StmtNodes.inc:879:1
  #17 0x0000000009f976fb (anonymous namespace)::ScalarExprEmitter::Visit(clang::Expr*) /tmp/clang/lib/CodeGen/CGExprScalar.cpp:410:3
  #18 0x0000000009fa4f82 (anonymous namespace)::ScalarExprEmitter::VisitBinAssign(clang::BinaryOperator const*) /tmp/clang/lib/CodeGen/CGExprScalar.cpp:4168:9
  #19 0x0000000009fa157d clang::StmtVisitorBase<std::add_pointer, (anonymous namespace)::ScalarExprEmitter, llvm::Value*>::Visit(clang::Stmt*) /tmp/clang/include/clang/AST/StmtVisitor.h:72:26
  #20 0x0000000009f976fb (anonymous namespace)::ScalarExprEmitter::Visit(clang::Expr*) /tmp/clang/lib/CodeGen/CGExprScalar.cpp:410:3
  #21 0x0000000009f97656 clang::CodeGen::CodeGenFunction::EmitScalarExpr(clang::Expr const*, bool) /tmp/clang/lib/CodeGen/CGExprScalar.cpp:4757:3
  #22 0x0000000009e5638c clang::CodeGen::CodeGenFunction::EmitAnyExpr(clang::Expr const*, clang::CodeGen::AggValueSlot, bool) /tmp/clang/lib/CodeGen/CGExpr.cpp:218:12
  #23 0x0000000009e562bd clang::CodeGen::CodeGenFunction::EmitIgnoredExpr(clang::Expr const*) /tmp/clang/lib/CodeGen/CGExpr.cpp:203:19
  #24 0x0000000009fc3616 clang::CodeGen::CodeGenFunction::EmitStmt(clang::Stmt const*, llvm::ArrayRef<clang::Attr const*>) /tmp/clang/lib/CodeGen/CGStmt.cpp:118:5
  #25 0x0000000009fcc7ab clang::CodeGen::CodeGenFunction::EmitCompoundStmtWithoutScope(clang::CompoundStmt const&, bool, clang::CodeGen::AggValueSlot) /tmp/clang/lib/CodeGen/CGStmt.cpp:447:3
  #26 0x0000000009e2ebd1 clang::CodeGen::CodeGenFunction::EmitFunctionBody(clang::Stmt const*) /tmp/clang/lib/CodeGen/CodeGenFunction.cpp:1187:5
  #27 0x0000000009e2f675 clang::CodeGen::CodeGenFunction::GenerateCode(clang::GlobalDecl, llvm::Function*, clang::CodeGen::CGFunctionInfo const&) /tmp/clang/lib/CodeGen/CodeGenFunction.cpp:1345:3
  #28 0x0000000009ce448e clang::CodeGen::CodeGenModule::EmitGlobalFunctionDefinition(clang::GlobalDecl, llvm::GlobalValue*) /tmp/clang/lib/CodeGen/CodeGenModule.cpp:4786:3
  #29 0x0000000009cdae4c clang::CodeGen::CodeGenModule::EmitGlobalDefinition(clang::GlobalDecl, llvm::GlobalValue*) /tmp/clang/lib/CodeGen/CodeGenModule.cpp:3172:12
  #30 0x0000000009cdfec4 clang::CodeGen::CodeGenModule::EmitGlobal(clang::GlobalDecl) /tmp/clang/lib/CodeGen/CodeGenModule.cpp:2925:5
  #31 0x0000000009ce7d10 clang::CodeGen::CodeGenModule::EmitTopLevelDecl(clang::Decl*) /tmp/clang/lib/CodeGen/CodeGenModule.cpp:5627:38
  #32 0x000000000a83b2c2 (anonymous namespace)::CodeGeneratorImpl::HandleTopLevelDecl(clang::DeclGroupRef) /tmp/clang/lib/CodeGen/ModuleBuilder.cpp:169:73
  #33 0x000000000a8356b4 clang::BackendConsumer::HandleTopLevelDecl(clang::DeclGroupRef) /tmp/clang/lib/CodeGen/CodeGenAction.cpp:215:12
  #34 0x000000000cf8fab5 clang::ParseAST(clang::Sema&, bool, bool) /tmp/clang/lib/Parse/ParseAST.cpp:162:20
  #35 0x000000000a65b742 clang::ASTFrontendAction::ExecuteAction() /tmp/clang/lib/Frontend/FrontendAction.cpp:1058:1
  #36 0x000000000a831709 clang::CodeGenAction::ExecuteAction() /tmp/clang/lib/CodeGen/CodeGenAction.cpp:1039:5
  #37 0x000000000a65b108 clang::FrontendAction::Execute() /tmp/clang/lib/Frontend/FrontendAction.cpp:953:7
  #38 0x000000000a52fa45 clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) /tmp/clang/lib/Frontend/CompilerInstance.cpp:955:23
  #39 0x000000000a81df96 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) /tmp/clang/lib/FrontendTool/ExecuteCompilerInvocation.cpp:278:8
  #40 0x0000000006103d0d cc1_main(llvm::ArrayRef<char const*>, char const*, void*) /tmp/clang/tools/driver/cc1_main.cpp:246:13
  #41 0x00000000060f6759 ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&) /tmp/clang/tools/driver/driver.cpp:335:5
  #42 0x00000000060f58ee main /tmp/clang/tools/driver/driver.cpp:412:5
  #43 0x00007ff3d11c70b3 __libc_start_main /build/glibc-eX1tMB/glibc-2.31/csu/../csu/libc-start.c:342:3
  #44 0x00000000060f509e _start (/tmp/build/bin/clang+0x60f509e)

This <https://github.com/llvm/llvm-project/blob/5d6b4aa80d6df62b924a12af030c5ded868ee4f1/llvm/lib/IR/Instructions.cpp#L2934> cast is failing. And my suspicion is that's because we are not handling matrix types here <https://github.com/llvm/llvm-project/blob/5d6b4aa80d6df62b924a12af030c5ded868ee4f1/llvm/lib/IR/Instructions.cpp#L3317-L3398>. It seems like we need to define a matrix type in `llvm/include/llvm/IR/Type.h` and use that to handle `castIsValid`.

Do you think this is the right approach?

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D99037/new/

https://reviews.llvm.org/D99037